665982857 has 2 divisors, whose sum is σ = 665982858. Its totient is φ = 665982856.

The previous prime is 665982841. The next prime is 665982929. The reversal of 665982857 is 758289566.

665982857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 619960201 + 46022656 = 24899^2 + 6784^2 .

It is a cyclic number.

It is not a de Polignac number, because 665982857 - 2⁴ = 665982841 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665982257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332991428 + 332991429.

It is an arithmetic number, because the mean of its divisors is an integer number (332991429).

Almost surely, 2^665982857 is an apocalyptic number.

It is an amenable number.

665982857 is a deficient number, since it is larger than the sum of its proper divisors (1).

665982857 is an equidigital number, since it uses as much as digits as its factorization.

665982857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7257600, while the sum is 56.

The square root of 665982857 is about 25806.6436601120. The cubic root of 665982857 is about 873.2816811743.

The spelling of 665982857 in words is "six hundred sixty-five million, nine hundred eighty-two thousand, eight hundred fifty-seven".